Revealing the impacts of recycled urea–formaldehyde wastes on the physical–mechanical properties of MDF

Dazmiri, Mohesn Khonakdar; Kiamahalleh, Mohammad Valizadeh; Kiamahalleh, Meisam Valizadeh; Mansouri, Hamid; Moazami, Vahid

doi:10.1007/s00107-018-1375-z

Cited by 19 publications

(5 citation statements)

References 25 publications

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“…Such extracts were also reported in the study by Hagel et al [42]. Another study [10] reported that, even at a hydrolysis temperature of 121 • C and a hydrolysis time of 30 min, the presence of amino compounds was observed in the pulp, indicating the disintegration of UF resin [47,48]. However, the impact of the hydrolysis regime on the physical and mechanical characteristics of MDF panels fabricated from recycled wood fibers obtained using the thermal hydrolysis of waste MDF panels was investigated in previous studies [10].…”

Section: Introductionsupporting

confidence: 64%

The Impact of Hydrolysis Regime on the Physical and Mechanical Characteristics of Medium-Density Fiberboards Manufactured from Recycled Wood Fibers

Savov,

Antov,

Panchev

et al. 2023

Fibers

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Recycling medium-density fiberboards (MDF) presents notable technological challenges, primarily due to the deteriorated properties of the recycled wood fibers obtained from MDF waste. On the other hand, the enhanced valorization of recycled wood in the manufacturing of wood composites represents a viable approach for implementing the principles of a circular bio-economy in the wood-based panel industry and lowering its carbon footprint. This research aimed to investigate and evaluate the impact of the hydrothermal hydrolysis regime on the physical and mechanical properties of recycled MDF panels (rMDF). The hydrolysis temperature was varied from 121 °C (saturated steam pressure 0.2 MPa) to 134 °C (saturated steam pressure 0.3 MPa), and three hydrolysis durations, i.e., 30, 45, and 60 min, were applied. A control MDF panel, manufactured in laboratory conditions from industrial pulp, was used to perform the comparative analyses. It was observed that the degradation of the rMDF panels occurred when the hydrolysis temperature was increased from 121 °C to 134 °C. The research confirmed the deteriorated physical and mechanical properties of rMDF compared to the panels manufactured from natural wood fibers. Markedly, no significant differences were detected between the density profiles of the rMDF panels and the control boards fabricated from industrial pulp. As a result of the study, it was found that the hydrolysis temperature has a more significant effect than the processing time. It was also established that, in the preliminary preparation of the MDF panels into samples with dimensions similar to those of pulp chips, the optimal hydrolysis regime is at a temperature of 121° C (saturated steam pressure 0.2 MPa) and a time of 30 min.

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Section: Introductionsupporting

confidence: 64%

The Impact of Hydrolysis Regime on the Physical and Mechanical Characteristics of Medium-Density Fiberboards Manufactured from Recycled Wood Fibers

Savov,

Antov,

Panchev

et al. 2023

Fibers

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“…Another study [39] corroborated these findings. In general, residual UF resin products, primarily amino groups, result in lower formaldehyde emissions from panels made from recycled fibers [52].…”

Section: Resultsmentioning

confidence: 99%

Effect of Hydrolysis Regime on the Properties of Fibers Obtained from Recycling Medium-Density Fiberboards

Savov,

Antov,

Panchev

et al. 2023

Fibers

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Unlike the recycling of particleboards, the recycling of medium-density fiberboards (MDF) is not a widespread industrial practice, and currently, most waste MDF panels are landfilled or incinerated after the end of their life cycle. Therefore, it is of great importance to develop cost-effective methods for MDF recycling. The extraction of resins used for bonding the panels, mostly urea–formaldehyde (UF) resins, is carried out mainly with hydrolysis. Hydrothermal hydrolysis is a more environmentally friendly and cheaper recycling technique compared to acid hydrolysis and allows obtaining a high yield of recycled fibers. The aim of this research work was to investigate and evaluate the effect of hydrolysis regime applied on its efficiency and on the properties of the recycled MDF fibers. For this purpose, thermal hydrolysis was carried out in an autoclave with saturated steam as a heat carrier. The main novelty of the research is the preliminary preparation of the recyclable MDF in samples with dimensions close to those of pulp chips. The effect of hydrolysis regime characteristics, i.e., process time and temperature on the properties of recycled MDF wood fibers, was studied. The hydrolysis temperatures used were 121 °C (saturated steam pressure of 0.2 MPa) and 134 °C (saturated steam pressure of 0.3 MPa); for each temperature, three durations were applied—30, 45, and 60 min. After hydrolysis, the resulting fiber fraction was refined using a hammer mill. The fractional and elemental composition of the recycled fibers obtained were evaluated. The hemicellulose content after each hydrolysis treatment was also determined. The chemical oxygen demand (COD) was defined as an indicator of wastewater contamination and as an indirect indicator of the quantitative yield of the process. The results revealed no significant changes in the elemental composition of the recycled fibers, and the hydrolysis regimes used showed no decrease in pentosan content. The recycled MDF fibers exhibited similar fiber morphology and fractional composition, being shorter than fibers from industrial pulp. The increased temperature and time of hydrolysis resulted in a significant increase in COD values. Based on the obtained results, with a view to the slightest contamination of wastewater (as determined by COD), the most promising hydrolysis regime was at a temperature of 121 °C and a time of 30 min. It should be emphasized that for a confirmation of this statement, the properties of MDF panels fabricated with fibers recycled in different regimes should be subsequently investigated.

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“…Moreover, MDF made from recycled fibers is difficult to compress but easier to spring back. Thus will contribute to the variations in panel density of recycled MDF (Dazmiri et al 2018;Hong et al 2020). 1.2-1.5 15-25 5.0-6.0 2.6-2.8 5.5-6.2 0.1-0.5 (Bütün et al 2018;Hong et al 2020;Hwang et al 2005;Lubis et al 2018a;Lykidis and Grigoriou 2008) Refining recycled 1.1-1.4 15-20 6.2-6.3 1.5-1.6 9.0-10.2 1.0-1.5…”

Section: Properties Of Recycled Fibersmentioning

confidence: 99%

The Removal of Cured Urea-Formaldehyde Adhesive towards Sustainable Medium Density Fiberboard Production: A Review

Manohar

Laksana²,

Fatriasari

et al. 2021

JSL

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Medium density fiberboard (MDF) is an engineered wood product that has density and specific gravity similar to solid wood, ranging from 600 to 800 kg/m3 of density and 0.6 to 0.8 of specific gravity. This makes MDF suitable to partially replace solid wood, particularly for interior application. Approximately over than 100 million m3 of MDF are produced in 2020, resulting in a large amount of waste MDF will be generated in the next 20 years. MDF is produced using urea-formaldehyde (UF) resins adhesive. UF resins adhesive is a poly-condensation product of urea and formaldehyde via an alkaline acid two-step reaction. Sustainable MDF production is required as the world is facing climate change and deforestation. Recycling is a way to support sustainable production in the engineered wood products manufacturing. Many attempts have been done to find ways to recycle waste MDF. The main problem is UF resins, which bond the MDF panel fibers. In order to re-manufacture the waste MDF into new recycled MDF, UF resins should be eliminated from the waste MDF before being used. The presence of UF resins in MDF can interfere with the utilization of the recycled fibers, whether it will be used as a raw material for new MDF or other composite products. This paper reviews the process of removal of cured UF resins from waste MDF panel by considering the hydrolytic stability of cured UF resins for MDF recycling, providing a comprehensive review of how cured UF resins can be removed from waste MDF and characterization of recycled fibers obtained from recycling prior to re-manufacturing of recycled MDF panel.Keywords: hydrolysis, medium density fiberboard, resin, recycling, resin removal, urea-formaldehyde

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Revealing the impacts of recycled urea–formaldehyde wastes on the physical–mechanical properties of MDF

Cited by 19 publications

References 25 publications

The Impact of Hydrolysis Regime on the Physical and Mechanical Characteristics of Medium-Density Fiberboards Manufactured from Recycled Wood Fibers

The Impact of Hydrolysis Regime on the Physical and Mechanical Characteristics of Medium-Density Fiberboards Manufactured from Recycled Wood Fibers

Effect of Hydrolysis Regime on the Properties of Fibers Obtained from Recycling Medium-Density Fiberboards

The Removal of Cured Urea-Formaldehyde Adhesive towards Sustainable Medium Density Fiberboard Production: A Review

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